Re: [PATCH -V8 09/16] mm/hugetlb: Add new HugeTLB cgroup

[Aneesh Kumar K.V]

Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> writes:

> (2012/06/09 17:59), Aneesh Kumar K.V wrote:
>> From: "Aneesh Kumar K.V"<aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>> 
>> This patch implements a new controller that allows us to control HugeTLB
>> allocations. The extension allows to limit the HugeTLB usage per control
>> group and enforces the controller limit during page fault.  Since HugeTLB
>> doesn't support page reclaim, enforcing the limit at page fault time implies
>> that, the application will get SIGBUS signal if it tries to access HugeTLB
>> pages beyond its limit. This requires the application to know beforehand
>> how much HugeTLB pages it would require for its use.
>> 
>> The charge/uncharge calls will be added to HugeTLB code in later patch.
>> Support for cgroup removal will be added in later patches.
>> 
>> Signed-off-by: Aneesh Kumar K.V<aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>
> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>
> some nitpick below.
>
>> ---
>>   include/linux/cgroup_subsys.h  |    6 +++
>>   include/linux/hugetlb_cgroup.h |   79 ++++++++++++++++++++++++++++
>>   init/Kconfig                   |   16 ++++++
>>   mm/Makefile                    |    1 +
>>   mm/hugetlb_cgroup.c            |  114 ++++++++++++++++++++++++++++++++++++++++
>>   5 files changed, 216 insertions(+)
>>   create mode 100644 include/linux/hugetlb_cgroup.h
>>   create mode 100644 mm/hugetlb_cgroup.c
>> 
>> diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
>> index 0bd390c..895923a 100644
>> --- a/include/linux/cgroup_subsys.h
>> +++ b/include/linux/cgroup_subsys.h
>> @@ -72,3 +72,9 @@ SUBSYS(net_prio)
>>   #endif
>> 
>>   /* */
>> +
>> +#ifdef CONFIG_CGROUP_HUGETLB_RES_CTLR
>> +SUBSYS(hugetlb)
>> +#endif
>> +
>> +/* */
>> diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
>> new file mode 100644
>> index 0000000..5794be4
>> --- /dev/null
>> +++ b/include/linux/hugetlb_cgroup.h
>> @@ -0,0 +1,79 @@
>> +/*
>> + * Copyright IBM Corporation, 2012
>> + * Author Aneesh Kumar K.V<aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms of version 2.1 of the GNU Lesser General Public License
>> + * as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it would be useful, but
>> + * WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>> + *
>> + */
>> +
>> +#ifndef _LINUX_HUGETLB_CGROUP_H
>> +#define _LINUX_HUGETLB_CGROUP_H
>> +
>> +#include<linux/res_counter.h>
>> +
>> +struct hugetlb_cgroup {
>> +	struct cgroup_subsys_state css;
>> +	/*
>> +	 * the counter to account for hugepages from hugetlb.
>> +	 */
>> +	struct res_counter hugepage[HUGE_MAX_HSTATE];
>> +};
>> +
>> +#ifdef CONFIG_CGROUP_HUGETLB_RES_CTLR
>> +static inline bool hugetlb_cgroup_disabled(void)
>> +{
>> +	if (hugetlb_subsys.disabled)
>> +		return true;
>> +	return false;
>> +}
>> +
>> +extern int hugetlb_cgroup_charge_page(int idx, unsigned long nr_pages,
>> +				      struct hugetlb_cgroup **ptr);
>> +extern void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
>> +					 struct hugetlb_cgroup *h_cg,
>> +					 struct page *page);
>> +extern void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
>> +					 struct page *page);
>> +extern void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
>> +					   struct hugetlb_cgroup *h_cg);
>> +#else
>> +static inline bool hugetlb_cgroup_disabled(void)
>> +{
>> +	return true;
>> +}
>> +
>> +static inline int
>> +hugetlb_cgroup_charge_page(int idx, unsigned long nr_pages,
>> +			   struct hugetlb_cgroup **ptr)
>> +{
>> +	return 0;
>> +}
>> +
>> +static inline void
>> +hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
>> +			     struct hugetlb_cgroup *h_cg,
>> +			     struct page *page)
>> +{
>> +	return;
>> +}
>> +
>> +static inline void
>> +hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, struct page *page)
>> +{
>> +	return;
>> +}
>> +
>> +static inline void
>> +hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
>> +			       struct hugetlb_cgroup *h_cg)
>> +{
>> +	return;
>> +}
>> +#endif  /* CONFIG_MEM_RES_CTLR_HUGETLB */
>> +#endif
>> diff --git a/init/Kconfig b/init/Kconfig
>> index d07dcf9..b9a0d0a 100644
>> --- a/init/Kconfig
>> +++ b/init/Kconfig
>> @@ -751,6 +751,22 @@ config CGROUP_MEM_RES_CTLR_KMEM
>>   	  the kmem extension can use it to guarantee that no group of processes
>>   	  will ever exhaust kernel resources alone.
>> 
>> +config CGROUP_HUGETLB_RES_CTLR
>> +	bool "HugeTLB Resource Controller for Control Groups"
>> +	depends on RESOURCE_COUNTERS&&  HUGETLB_PAGE&&  EXPERIMENTAL
>> +	select PAGE_CGROUP
>> +	default n
>> +	help
>> +	  Provides a simple cgroup Resource Controller for HugeTLB pages.
>
> what you want to say by adding 'simple' here ?
>

removed

>
>> +	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
>> +	  The limit is enforced during page fault. Since HugeTLB doesn't
>> +	  support page reclaim, enforcing the limit at page fault time implies
>> +	  that, the application will get SIGBUS signal if it tries to access
>> +	  HugeTLB pages beyond its limit. This requires the application to know
>> +	  beforehand how much HugeTLB pages it would require for its use. The
>> +	  control group is tracked in the third page lru pointer. This means
>> +	  that we cannot use the controller with huge page less than 3 pages.
>> +
>>   config CGROUP_PERF
>>   	bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
>>   	depends on PERF_EVENTS&&  CGROUPS
>> diff --git a/mm/Makefile b/mm/Makefile
>> index a156285..a8dd8d5 100644
>> --- a/mm/Makefile
>> +++ b/mm/Makefile
>> @@ -48,6 +48,7 @@ obj-$(CONFIG_MIGRATION) += migrate.o
>>   obj-$(CONFIG_QUICKLIST) += quicklist.o
>>   obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o
>>   obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o
>> +obj-$(CONFIG_CGROUP_HUGETLB_RES_CTLR) += hugetlb_cgroup.o
>>   obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
>>   obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
>>   obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
>> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
>> new file mode 100644
>> index 0000000..20a32c5
>> --- /dev/null
>> +++ b/mm/hugetlb_cgroup.c
>> @@ -0,0 +1,114 @@
>> +/*
>> + *
>> + * Copyright IBM Corporation, 2012
>> + * Author Aneesh Kumar K.V<aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms of version 2.1 of the GNU Lesser General Public License
>> + * as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it would be useful, but
>> + * WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>> + *
>> + */
>> +
>> +#include<linux/cgroup.h>
>> +#include<linux/slab.h>
>> +#include<linux/hugetlb.h>
>> +#include<linux/hugetlb_cgroup.h>
>> +
>> +struct cgroup_subsys hugetlb_subsys __read_mostly;
>> +struct hugetlb_cgroup *root_h_cgroup __read_mostly;
>> +
>> +static inline
>> +struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s)
>> +{
>> +	if (s)
>> +		return container_of(s, struct hugetlb_cgroup, css);
>> +	return NULL;
>> +}
>> +
>> +static inline
>> +struct hugetlb_cgroup *hugetlb_cgroup_from_cgroup(struct cgroup *cgroup)
>> +{
>> +	return hugetlb_cgroup_from_css(cgroup_subsys_state(cgroup,
>> +							   hugetlb_subsys_id));
>> +}
>> +
>> +static inline
>> +struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
>> +{
>> +	return hugetlb_cgroup_from_css(task_subsys_state(task,
>> +							 hugetlb_subsys_id));
>> +}
>> +
>> +static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
>> +{
>> +	return (h_cg == root_h_cgroup);
>> +}
>> +
>> +static inline struct hugetlb_cgroup *parent_hugetlb_cgroup(struct cgroup *cg)
>> +{
>> +	if (!cg->parent)
>> +		return NULL;
>> +	return hugetlb_cgroup_from_cgroup(cg->parent);
>> +}
>> +
>> +static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg)
>> +{
>> +	int idx;
>> +	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cg);
>> +
>> +	for (idx = 0; idx<  hugetlb_max_hstate; idx++) {
>> +		if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE))>  0)
>> +			return 1;
>> +	}
>> +	return 0;
>> +}
>
> How about using true/false rather than 0/1 ?


done

>
>
>> +
>> +static struct cgroup_subsys_state *hugetlb_cgroup_create(struct cgroup *cgroup)
>> +{
>> +	int idx;
>> +	struct cgroup *parent_cgroup;
>> +	struct hugetlb_cgroup *h_cgroup, *parent_h_cgroup;
>> +
>> +	h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
>> +	if (!h_cgroup)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	parent_cgroup = cgroup->parent;
>> +	if (parent_cgroup) {
>> +		parent_h_cgroup = hugetlb_cgroup_from_cgroup(parent_cgroup);
>> +		for (idx = 0; idx<  HUGE_MAX_HSTATE; idx++)
>                                 ^^^
> add space is better.

I don't have that in my patch. I also don't see the original
mail. checkpatch will warn about such errors and i didn't get any such
warnings. So it mostly is a error on your mail client ?

>
>> +			res_counter_init(&h_cgroup->hugepage[idx],
>> +					&parent_h_cgroup->hugepage[idx]);
>> +	} else {
>> +		root_h_cgroup = h_cgroup;
>> +		for (idx = 0; idx<  HUGE_MAX_HSTATE; idx++)
>                                 ^^^
>
>> +			res_counter_init(&h_cgroup->hugepage[idx], NULL);
>> +	}
>> +	return&h_cgroup->css;
>              ^^^
> ditto.
>
>> +}
>> +
>> +static void hugetlb_cgroup_destroy(struct cgroup *cgroup)
>> +{
>> +	struct hugetlb_cgroup *h_cgroup;
>> +
>> +	h_cgroup = hugetlb_cgroup_from_cgroup(cgroup);
>> +	kfree(h_cgroup);
>> +}
>> +
>> +static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)
>> +{
>> +	/* We will add the cgroup removal support in later patches */
>> +	   return -EBUSY;
>> +}
>
> -ENOTSUP rather than -BUSY :p

The later patch remove this. What I wanted in the intermediate patches
is to state that we are not ready to be removed because we have some
charges.

>
>> +
>> +struct cgroup_subsys hugetlb_subsys = {
>> +	.name = "hugetlb",
>> +	.create     = hugetlb_cgroup_create,
>> +	.pre_destroy = hugetlb_cgroup_pre_destroy,
>> +	.destroy    = hugetlb_cgroup_destroy,
>> +	.subsys_id  = hugetlb_subsys_id,
>> +};
>
>
> Thanks,
> -Kame

-aneesh

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